Thermal Hall Effect of Chiral Spin Fluctuations

TL;DR

This paper demonstrates that chiral spin fluctuations in a 2D Heisenberg model can induce a thermal Hall effect without static textures or topological band structures, especially at high temperatures.

Contribution

It reveals a novel mechanism for thermal Hall effect driven by dynamic spin fluctuations, expanding understanding beyond static textures and topological magnons.

Findings

Thermal Hall response is finite at high temperatures.

Chiral spin fluctuations induce nontrivial topology.

Effect persists outside linear spin wave regime.

Abstract

Using a two-dimensional square lattice Heisenberg model with a Rashba-type Dzyaloshinskii-Moriya interaction, we demonstrate that chiral spin fluctuations can give rise to a thermal Hall effect in the absence of any static spin texture or momentum space topology. It is shown by means of Monte Carlo and stochastic spin dynamics simulations that the thermal Hall response is finite at elevated temperature outside of the linear spin wave regime and consistent with the presence of thermal fluctuation-induced nontrivial topology. Our result suggests that the high-fluctuation phases outside of the conventional regime of magnonics may yet be a promising area of exploration for spin-based electronics.